1 /* 2 * Route Plug-In 3 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org> 4 * 5 * 6 * This library is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU Library General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU Library General Public License for more details. 15 * 16 * You should have received a copy of the GNU Library General Public 17 * License along with this library; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 * 20 */ 21 22 #include <linux/slab.h> 23 #include <linux/time.h> 24 #include <sound/core.h> 25 #include <sound/pcm.h> 26 #include "pcm_plugin.h" 27 28 static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts, 29 snd_pcm_uframes_t frames, int format) 30 { 31 int dst = 0; 32 for (; dst < ndsts; ++dst) { 33 if (dvp->wanted) 34 snd_pcm_area_silence(&dvp->area, 0, frames, format); 35 dvp->enabled = 0; 36 dvp++; 37 } 38 } 39 40 static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel, 41 struct snd_pcm_plugin_channel *dst_channel, 42 snd_pcm_uframes_t frames, int format) 43 { 44 dst_channel->enabled = 1; 45 snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format); 46 } 47 48 static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin, 49 const struct snd_pcm_plugin_channel *src_channels, 50 struct snd_pcm_plugin_channel *dst_channels, 51 snd_pcm_uframes_t frames) 52 { 53 int nsrcs, ndsts, dst; 54 struct snd_pcm_plugin_channel *dvp; 55 int format; 56 57 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO); 58 if (frames == 0) 59 return 0; 60 61 nsrcs = plugin->src_format.channels; 62 ndsts = plugin->dst_format.channels; 63 64 format = plugin->dst_format.format; 65 dvp = dst_channels; 66 if (nsrcs <= 1) { 67 /* expand to all channels */ 68 for (dst = 0; dst < ndsts; ++dst) { 69 copy_area(src_channels, dvp, frames, format); 70 dvp++; 71 } 72 return frames; 73 } 74 75 for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) { 76 copy_area(src_channels, dvp, frames, format); 77 dvp++; 78 src_channels++; 79 } 80 if (dst < ndsts) 81 zero_areas(dvp, ndsts - dst, frames, format); 82 return frames; 83 } 84 85 int snd_pcm_plugin_build_route(struct snd_pcm_substream *plug, 86 struct snd_pcm_plugin_format *src_format, 87 struct snd_pcm_plugin_format *dst_format, 88 struct snd_pcm_plugin **r_plugin) 89 { 90 struct snd_pcm_plugin *plugin; 91 int err; 92 93 snd_assert(r_plugin != NULL, return -ENXIO); 94 *r_plugin = NULL; 95 snd_assert(src_format->rate == dst_format->rate, return -ENXIO); 96 snd_assert(src_format->format == dst_format->format, return -ENXIO); 97 98 err = snd_pcm_plugin_build(plug, "route conversion", 99 src_format, dst_format, 0, &plugin); 100 if (err < 0) 101 return err; 102 103 plugin->transfer = route_transfer; 104 *r_plugin = plugin; 105 return 0; 106 } 107